The 'Grey's Anatomy' alum will recur on the upcoming anthology series.

T.R. Knight is headed to National Geographic.

The Grey's Anatomy alum has joined the cabler's upcoming anthology series Genius: Einstein in a recurring role, The Hollywood Reporter has learned.

Knight will play real-life figure J. Edgar Hoover, the first Director of the Federal Bureau of Investigation of the United States, at different ages over multiple decades. Under Hoover's direction, the FBI amassed an enormous file on Albert Einstein (Geoffrey Rush) in an attempt to prove that he was a “subversive” and a secret Communist. Hoover became intent on ruining Einstein, developing a personal vendetta against the famous scientist following incidents in which he perceived that Einstein had humiliated the U.S. government.

The 10-episode Genius will chart how an imaginative, rebellious patent clerk, who couldn’t get a teaching job or a doctorate, unlocked the mysteries of the atom and the universe. Each episode will explore Einstein’s scientific achievements, along with his volatile, passionate and complex personal relationships. The first season is based on Walter Isaacson’s critically acclaimed biography Einstein: His Life and Universe.

Knight follows an impressive group of actors that have portrayed Hoover, including Leonardo DiCaprio, Kelsey Grammer, Bob Hoskins, Billy Crudup, Dylan Baker and most recently Stephen Root in HBO's All the Way.

Best known for his Emmy-nominated performance on Grey's Anatomy, Knight will next be seen in the ABC gay-rights miniseries When We Rise before he makes a return trip to Shondaland, joining the upcoming second season of The Catch. His other credits include The Good Wife and 11.22.63. Knight is repped by Gersh.